Treesearch

Forested ecosystems are shaped by climate, soil and biotic interactions, resulting in constrained spatial distribution of species and biomes. Tolerance traits of species determine their fundamental ecological niche, while biotic interactions narrow tree distributions to the realized niche. In particular, shade, drought and waterlogging tolerances have been well-characterized at the species level in the Northern hemisphere tree species. Species distribution models explore fundamental niches and current geographic distributions with respect to environmental factors, but their ability to...

The state of Oregon recently invested in exploring options for increasing the extent of forest restoration activity. This initiative aims to reduce the incidence, effects, and expense of catastrophic fire events and restore economic stability to rural communities by enhancing the supply of raw materials for wood processing facilities and wood-based, renewable energy producers, particularly in the comparatively xeric, eastern two-thirds of the State. Collaborating with PNW-FIA and Portland State University, the Oregon Department of Forestry evaluated current levels of fire hazard as...

In many forest inventories, statistical models are employed to predict values for attributes that are difficult and/or time-consuming to measure. In some applications, models are applied across a large geographic area, which assumes the relationship between the response variable and predictors is ubiquitously invariable within the area. The extent to which this assumption holds for a tree height prediction model was evaluated at regional, ecoprovince, and ecosection spatial scales in the Northeastern United States. Two nonlinear regression models were tested, a spatially-ambiguous model...

Thousand cankers disease (TCD) is a new disease of black walnut (Juglans nigra L.) in the eastern United States. The disease is caused by the interaction of the aggressive bark beetle Pityophthorus juglandis Blackman and the canker-forming fungus, Geosmithia morbida M. Kolarik, E. Freeland, C. Utley & Tisserat, carried by the beetle. Other insects also colonize TCD-symptomatic trees and may also carry pathogens. A trap tree survey was conducted in Indiana and Missouri to characterize the assemblage of ambrosia beetles, bark beetles, and other weevils attracted to the main stems and crowns...

The canker pathogen Geosmithia morbida is known to be transmitted to Juglans species by the bark beetle Pityophthorus juglandis, and to lead to development of thousand cankers disease. In an Indiana-wide trap-tree survey of ambrosia and bark beetles and weevils colonizing stressed Juglans nigra, G. morbida was detected on three Stenomimus pallidus weevils emerged from two trees on one site. This is the first report of the pathogen in Indiana and the first report of the fungus from an insect species other than P. juglandis.

Urban forest strategies of gradually replacing high emitters of biogenic volatile organic compounds (BVOC) with low-emitting species are being considered as voluntary or emerging control measures for maintenance of the 8-h ozone standard in the Sacramento Federal Non-Attainment Area (SFNA). We describe a regulatory modeling study demonstrating the air-quality impacts of such measures as well as of strategies that increase net canopy cover. The results indicate that changing the mix of urban trees can improve air quality. The daily reductions in ozone resulting from species replacement...

The North American Forest Dynamics (NAFD) project’s Attribution Team is completing nationwide processing of historic Landsat data to provide a comprehensive annual, wall-to-wall analysis of US disturbance history, with attribution, over the last 25+ years. Per-pixel time series analysis based on a new nonparametric curve fitting algorithm yields several metrics useful for elucidating causal processes underlying forest disturbance dynamics but requires CPU-intensive computation across large data sets (>4 billion pixels classified as forest in 434 Landsat scenes covering the conterminous...

Surface ozone (O3) concentrations were measured in and around the Lake Tahoe Basin using both active monitors (2010) and passive samplers (2002, 2010). The 2010 data from active monitors indicate average summertime diurnal maxima of approximately 50–55 ppb. Some site-to-site variability is observed within the Basin during the well-mixed hours of 10:00 to 17:00 PST, but large differences between different sites are observed in the late evening and pre-dawn hours. The observed trends correlate most strongly with elevation, topography, and surface vegetation. High elevation sites with steeply...

Understanding changes in land use and land cover over space and time provides an important means to evaluate complex interactions between human and biophysical systems, to project future conditions, and to design mitigation and adaptive management strategies. Assessing and monitoring landscape change is evolving into a foundational element of climate change adaptation, ecological restoration, and resource sustainability. Landscape change data are core to Forest Service functions including: land management planning, restoration analysis, carbon accounting, greenhouse gas emission reporting,...

The USDA Forest Service is evaluating the status of current landscape change maps and assessing gaps in their information content. These activities have been occurring under the auspices of the Landscape Change Monitoring System (LCMS) project, which is a joint effort between USFS Research, USFS Remote Sensing Applications Center (RSAC), USGS Earth Resources Observation and Science (EROS) Center, and academic partners. One of the early needs identified was a system that facilitated the visual comparison of several change maps in a common visualization framework. The application presented...